In my other issue #371 (comment) you mentioned that animals will be hurt by high levels of radiation, but even when I dropped a stack of HECf-251 Oxide Fuel which showed as 71 rads/t being emitted in that chunk, none of the animals/villagers were affected. Hostile mobs are significantly buffed.

MC: 1.12.2
Forge: 14.23.5.2768
Nuclearcraft: 2.12e--1.12.2

EDIT:
default configs for everything except enabling radiation and restarting client afterwards, then creating the world in creative.

Turns out animals need the potion effects to have at least some finite lasting time to do anything, unlike both the player and mobs - fixed!